Help with Kohler CV740 after rebuild!

[ILENGINE]

Are you sure you didn't switch the heads around, there is a cylinder #1 and #2. You must install the heads on the correct cylinder.

I thought about that to Rivets, but also thought that if they were on the wrong side the exhaust and intake ports would be upside down.

He has a compression problem. I have considered the timing is incorrect and the valves are opening and closing at the wrong time. but without the pushrods in place he should have compression, unless the fact the intake valve isn't opening and can draw in air there is nothing to compress.

I think if it was mine I would try a leakdown test and make sure there isn't a ring problem or some other problem causing lack of compression. After that I would be rechecking the camshaft timing.

 

[Rivets]

Yes, I understand that it is unlikely, but on this forum and at the shop over the years I have seen very odd things. I agree that a leak down test would provide some answers and eliminate some possible problems. I would also try to figure out why the pushrods bent. I just had to replace a head where the valve guides came loose, not allowing the rockers full travel.

 

[jallen2845]

Alright guys, I think we have a winner. Please don't blast me for this, I feel like enough of a dumba$$ already! I came to the forum for help (as I have done with many things in the past) and I think you guys have helped me figure it out...but boy do I feel stupid. When I put the camshaft in, it never dawned on me about timing. I did not put the cam in the proper way so the engine timing is off. I have a basic knowledge of how engines work, and have worked on many aircooled VW engines, but like I said this is my first time inside a small engine like this. I just stuck the cam in there. Stupid me. That would explain the bent rod (possibly contributed to by not compressing the hydraulic lifters) and the lack of compression. The only thing that doesn't make sense is no compression with the push rods removed, unless as ILENGINE said, there is no air to compress since the intake valves aren't opening, and that sounds very plausible.

So...my questions now are:

1. This sounds like the answer, correct?
2. Is there a timing mark on the cam and how do I assure that it is in time when I put it in?
3. Do I need to order new headgaskets again or can I reuse the ones that I just bought and installed?

Thanks for all the help!

 

[ILENGINE]

There is a dot next to a tooth or between two teeth on the crankshaft gear, and the camshaft gear. Line up the two dots. Since the engine hasn't been run, and if the gaskets aren't damaged I would try to reuse them.

Don't feel bad about the timing marks on the gears. I had a customer bring me a 5 hp briggs around 10 years ago that he had totally disassembled including removing the rings from the piston, and brought to me in a cardboard box. He was trying to find out why it wouldn't start and run. I had to reassemble the engine, install new gaskets, and find out cause of his starting problem.

Final cause of failure to run was a faulty spark plug.

 

[grumpyunk]

I was going to vote for stuck valves, but mistimed cam apparently can cause the same problem. If the pushrod got bent on an engine just cranking over, there was an interference problem of some kind. A valve guide migrating out of the head, a sticky valve, or in this case, valve timing allowing the piston to cram into the valve are the likely suspects.
I would re-use the head gasket, torquing it in three steps to the final torque value, using the factory specified pattern. If none, do criss-cross on the bolts, walking up and down and side to side.
There will be a significant change in crankcase pressure as the pistons move in their travel. They will cause low pressure on the up(compression/exhaust) stroke and higher pressure on the down stroke(intake / firing). Twins can also cause the same thing with possibly more pressure if they are opposed and have opposite strokes.
That pulse is used by some makers to power the fuel pump. Older Kohlers used a lobe on the cam with a mechanical follower.
tom

 

[jallen2845]

Is is safe to assume that the only damage is the pushrod from it being out of time and that the valves and piston are ok? I will visually inspect when I tear it back down of course.

 

[Rivets]

Check page 11.4 of this manual for help on the timing make alignment.

http://www.mymowerparts.com/pdf/Koh...d-CV17-CV18-CV20-CV22-CV25-CV22-CV23-CV26.pdf

 

[grumpyunk]

If it is still apart, I would pull the valve that had the bent pushrod, and twirl it to see that it is not bent.
I would not re-use the pushrod. I know I cannot make one 'straight' even rolling it back and forth on a chunk of glass or steel. Any bend will be amplified when it is under load and cycling back and forth at 1800cps.
Meant to metion that the hydraulic lifters are supposedly the same as Chevy small block, but don't bet the payroll on that. In addition, a fully pumped hydraulic lifter should not provide excessive lift such that it will bend a pushrod. If it were full of oil, then the time it takes from assembly to installation should be long enough for bleed down to take place, and there is a pathway for oil to leak out the top into the pushrod as the lifter cycles from loaded to un-loaded. The load/unload will meter the oil fed to the pushrod as the internal piston moves that tiny bit and lets oil have an 'opportunity' to enter the internal chamber to take up any slack in the valve train.
tom